Power stations, also known as power plants, serve as industrial facilities for generating electric power. In general, many of these power plants rely on coal as the source of energy to generate electricity. These power plants can burn a significant amount of coal per day, e.g. 15,000 tons, at a particular heat value, e.g. 12,200 BTU/pound (British Thermal Unit/pound) for a larger facility. Frequently, coal power plants are located at or near coal mines in order to reduce the costs of obtaining and transporting the coal to the power plant. Thus, these coal power plants are designed to burn coal with the particular characteristics of the nearby coal (e.g., heat value or sulfur content). However, when the coal power plant operations eventually exhaust the economically feasible onsite or nearby coal reserves, the power plants must begin to use coal delivered from other sources. The heat value of the offsite coal may differ drastically from the value of the onsite coal, and, thus, power plants are faced with the problem of using coal that does not match the design parameters of the power plant, which can either reduce the efficiency of the power plant if the offsite coal has a lower heat value or significantly increase the fuel costs by burning higher-than-necessary quality coals.
In addition to the differing heat values, the offsite coal may have differing levels of undesirable non-carbon based elements or other components that adversely affect either the operating efficiency of the boilers that produce the steam for the power plant or the emission limits for the permits held by the power plant. For instance, the presence of too much sulfur or mercury in the coal can cause the power plant emissions to exceed the allowable levels under the applicable permits. The presence of too much ash (and rock and other non-carbon based elements) or moisture can interfere with the efficiency of the boilers and cause a reduction in the overall efficiency of the power plant.
Power plant operators have partially solved these problems by bringing in various grades of offsite coal and manually blending them in order to crudely create a blended coal at roughly the desired heat value or properties for the particular plant. However, this blending is often done by manually mixing one type of offsite coal with another using bulldozers or other moving equipment, which lacks precision in uniformly blending the coal to a specific heat value or property. It also lacks the ability to precisely control the characteristics of the blended coal. Because of the crude nature of the mixing, different portions of the blended coal will have very different characteristics even if the average characteristics meet the desired target values.
Because coal from multiple sources can vary greatly in terms of quality and the mixing is imprecise and not uniform, most power plants will limit their intake and rely on two sources of offsite coal in order to reduce the need for blending the coal as much as possible, or the power plants may choose to procure a higher quality more expensive product that exceeds the optimum burn quality requirement to avoid coal quality issues. As a result, these coal power plants (a) rely on limited coal sources instead of being able to receive coal from any number of providers, (b) blend few types of coal on site manually without much precision or uniformity of the overall blended product, and (c) lack the capacity to blend coal from many sources in an efficient, precise, and uniform manner to meet varying fuel, efficiency, or regulatory requirements.